AR
- .ar
- A.r. group
- AR (EP)
- AR-15–style rifle
- ARTV (disambiguation)
- Absolute Return + Alpha
- Accelerated Reader
- Accounts receivable
- Acoustic Research
- Adaptive routing
- Adobe Aero
- Aerojet Rocketdyne
- Aerolíneas Argentinas
- Affirmative Repositioning
- Alfa Romeo
- Alternate reality (disambiguation)
- American Renaissance (magazine)
- Androgen receptor
- Animal rights
- Animal rights movement
- Anti-reflective coating
- Antipodean Resistance
- Aortic regurgitation
- Appenzell Ausserrhoden
- Aqua regia
- Ar (city)
- Ar (cuneiform)
- Arabic
- Archimedes number
- Architectural Review
- Argent
- Argentina
- Argon
- Arkansas
- Armalite Rifle
- Armeerundschau
- Armstrong–Ringsted Community School District
- Army Reserve (Ireland)
- Artists and repertoire
- Arunachal Pradesh
- Aryl group
- Aspect ratio (aeronautics)
- Assistant referee (association football)
- AtkinsRéalis
- Augmented reality
- Auto rickshaw
- Autoregressive model
- Autosomal recessive inheritance
- Avis de réception
- Gor
- List of auxiliaries of the United States Navy
- List of numismatic abbreviations
- Province of Arezzo
- R
- Relative atomic mass
- The Adelaide Review
- Toyota AR engine